用样本均数推论总体均数95%可信区间的公式是(总体标准差未知且样本量较小)

A、[img=~/QImg/2013-10-14-10-46-38/image106.gif]ρt0.05,υS[img=~/QImg/2013-10-14-10-46-38/image106.gif]
B、[img=~/QImg/2013-10-14-10-46-38/image106.gif]ρt0.01,υS[img=~/QImg/2013-10-14-10-46-38/image106.gif]
C、[img=~/QImg/2013-10-14-10-46-38/image106.gif]ρ1.96S[img=~/QImg/2013-10-14-10-46-38/image106.gif]
D、[img=~/QImg/2013-10-14-10-46-38/image106.gif]ρ2.58S[img=~/QImg/2013-10-14-10-46-38/image106.gif]
E、以上都不对